XGate

class qiskit.circuit.library.XGate(label=None)

Bases: Gate

The single-qubit Pauli-X gate ( $\sigma_x$ ).

Can be applied to a QuantumCircuit with the x() method.

Matrix Representation:

\begin{split}X = \begin{pmatrix} 0 & 1 \\ 1 & 0 \end{pmatrix}\end{split}

Circuit symbol:

     ┌───┐
q_0: ┤ X ├
     └───┘

Equivalent to a $\pi$ radian rotation about the X axis.

Note

A global phase difference exists between the definitions of $RX(\pi)$ and $X$ .

\begin{split}RX(\pi) = \begin{pmatrix} 0 & -i \\ -i & 0 \end{pmatrix} = -i X\end{split}

The gate is equivalent to a classical bit flip.

\begin{split}|0\rangle \rightarrow |1\rangle \\ |1\rangle \rightarrow |0\rangle\end{split}

Create new X gate.

Attributes

Get Clbits in condition.

Get the decompositions of the instruction from the SessionEquivalenceLibrary.

Return definition in terms of other basic gates.

Get the duration.

Return instruction label

Return the name.

Return the number of clbits.

Return the number of qubits.

return instruction params.

Get the time unit of duration.

control(num_ctrl_qubits=1, label=None, ctrl_state=None)

Return a (multi-)controlled-X gate.

One control returns a CX gate. Two controls returns a CCX gate.

Parameters

num_ctrl_qubits (int) – number of control qubits.
label (str or None) – An optional label for the gate [Default: None]
ctrl_state (int orstr or None) – control state expressed as integer, string (e.g. ‘110’), or None. If None, use all 1s.

Returns

controlled version of this gate.

Return type

ControlledGate

inverse()

Return inverted X gate (itself).

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